<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<script src="../js/vue.js"></script>
<div id="app">
  <h2>{{counter}}</h2>
<!--  <button v-on:click="increment()">++++++</button>-->
<!--  <button v-on:click="decrement()">&#45;&#45;&#45;&#45;&#45;&#45;</button>-->
  <button @click="increment()">++++++</button>
  <button @click="decrement()">------</button>
</div>
<script>
    const app = new Vue({
        el:'#app',
      data:{
          counter:0
      },
        methods:{
          increment(){
            return this.counter++;
          },
          decrement(){
            return this.counter--;
          }
        }

    })
</script>

</body>
</html>